/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.beans;

import java.util.Map;

import org.springframework.core.convert.TypeDescriptor;
import org.springframework.lang.Nullable;

/**
 * Common interface for classes that can access named properties
 * (such as bean properties of an object or fields in an object)
 * Serves as base interface for {@link BeanWrapper}.
 *
 * @author Juergen Hoeller
 * @see BeanWrapper
 * @see PropertyAccessorFactory#forBeanPropertyAccess
 * @see PropertyAccessorFactory#forDirectFieldAccess
 * @since 1.1
 */
public interface PropertyAccessor {

    /**
     * Path separator for nested properties.
     * Follows normal Java conventions: getFoo().getBar() would be "foo.bar".
     */
    String NESTED_PROPERTY_SEPARATOR = ".";

    /**
     * Path separator for nested properties.
     * Follows normal Java conventions: getFoo().getBar() would be "foo.bar".
     */
    char NESTED_PROPERTY_SEPARATOR_CHAR = '.';

    /**
     * Marker that indicates the start of a property key for an
     * indexed or mapped property like "person.addresses[0]".
     */
    String PROPERTY_KEY_PREFIX = "[";

    /**
     * Marker that indicates the start of a property key for an
     * indexed or mapped property like "person.addresses[0]".
     */
    char PROPERTY_KEY_PREFIX_CHAR = '[';

    /**
     * Marker that indicates the end of a property key for an
     * indexed or mapped property like "person.addresses[0]".
     */
    String PROPERTY_KEY_SUFFIX = "]";

    /**
     * Marker that indicates the end of a property key for an
     * indexed or mapped property like "person.addresses[0]".
     */
    char PROPERTY_KEY_SUFFIX_CHAR = ']';


    /**
     * Determine whether the specified property is readable.
     * <p>Returns {@code false} if the property doesn't exist.
     *
     * @param propertyName the property to check
     *                     (may be a nested path and/or an indexed/mapped property)
     * @return whether the property is readable
     */
    boolean isReadableProperty(String propertyName);

    /**
     * Determine whether the specified property is writable.
     * <p>Returns {@code false} if the property doesn't exist.
     *
     * @param propertyName the property to check
     *                     (may be a nested path and/or an indexed/mapped property)
     * @return whether the property is writable
     */
    boolean isWritableProperty(String propertyName);

    /**
     * Determine the property type for the specified property,
     * either checking the property descriptor or checking the value
     * in case of an indexed or mapped element.
     *
     * @param propertyName the property to check
     *                     (may be a nested path and/or an indexed/mapped property)
     * @return the property type for the particular property,
     * or {@code null} if not determinable
     * @throws PropertyAccessException if the property was valid but the
     *                                 accessor method failed
     */
    @Nullable
    Class<?> getPropertyType(String propertyName) throws BeansException;

    /**
     * Return a type descriptor for the specified property:
     * preferably from the read method, falling back to the write method.
     *
     * @param propertyName the property to check
     *                     (may be a nested path and/or an indexed/mapped property)
     * @return the property type for the particular property,
     * or {@code null} if not determinable
     * @throws PropertyAccessException if the property was valid but the
     *                                 accessor method failed
     */
    @Nullable
    TypeDescriptor getPropertyTypeDescriptor(String propertyName) throws BeansException;

    /**
     * Get the current value of the specified property.
     *
     * @param propertyName the name of the property to get the value of
     *                     (may be a nested path and/or an indexed/mapped property)
     * @return the value of the property
     * @throws InvalidPropertyException if there is no such property or
     *                                  if the property isn't readable
     * @throws PropertyAccessException  if the property was valid but the
     *                                  accessor method failed
     */
    @Nullable
    Object getPropertyValue(String propertyName) throws BeansException;

    /**
     * Set the specified value as current property value.
     *
     * @param propertyName the name of the property to set the value of
     *                     (may be a nested path and/or an indexed/mapped property)
     * @param value        the new value
     * @throws InvalidPropertyException if there is no such property or
     *                                  if the property isn't writable
     * @throws PropertyAccessException  if the property was valid but the
     *                                  accessor method failed or a type mismatch occurred
     */
    void setPropertyValue(String propertyName, @Nullable Object value) throws BeansException;

    /**
     * Set the specified value as current property value.
     *
     * @param pv an object containing the new property value
     * @throws InvalidPropertyException if there is no such property or
     *                                  if the property isn't writable
     * @throws PropertyAccessException  if the property was valid but the
     *                                  accessor method failed or a type mismatch occurred
     */
    void setPropertyValue(PropertyValue pv) throws BeansException;

    /**
     * Perform a batch update from a Map.
     * <p>Bulk updates from PropertyValues are more powerful: This method is
     * provided for convenience. Behavior will be identical to that of
     * the {@link #setPropertyValues(PropertyValues)} method.
     *
     * @param map a Map to take properties from. Contains property value objects,
     *            keyed by property name
     * @throws InvalidPropertyException     if there is no such property or
     *                                      if the property isn't writable
     * @throws PropertyBatchUpdateException if one or more PropertyAccessExceptions
     *                                      occurred for specific properties during the batch update. This exception bundles
     *                                      all individual PropertyAccessExceptions. All other properties will have been
     *                                      successfully updated.
     */
    void setPropertyValues(Map<?, ?> map) throws BeansException;

    /**
     * The preferred way to perform a batch update.
     * <p>Note that performing a batch update differs from performing a single update,
     * in that an implementation of this class will continue to update properties
     * if a <b>recoverable</b> error (such as a type mismatch, but <b>not</b> an
     * invalid field name or the like) is encountered, throwing a
     * {@link PropertyBatchUpdateException} containing all the individual errors.
     * This exception can be examined later to see all binding errors.
     * Properties that were successfully updated remain changed.
     * <p>Does not allow unknown fields or invalid fields.
     *
     * @param pvs a PropertyValues to set on the target object
     * @throws InvalidPropertyException     if there is no such property or
     *                                      if the property isn't writable
     * @throws PropertyBatchUpdateException if one or more PropertyAccessExceptions
     *                                      occurred for specific properties during the batch update. This exception bundles
     *                                      all individual PropertyAccessExceptions. All other properties will have been
     *                                      successfully updated.
     * @see #setPropertyValues(PropertyValues, boolean, boolean)
     */
    void setPropertyValues(PropertyValues pvs) throws BeansException;

    /**
     * Perform a batch update with more control over behavior.
     * <p>Note that performing a batch update differs from performing a single update,
     * in that an implementation of this class will continue to update properties
     * if a <b>recoverable</b> error (such as a type mismatch, but <b>not</b> an
     * invalid field name or the like) is encountered, throwing a
     * {@link PropertyBatchUpdateException} containing all the individual errors.
     * This exception can be examined later to see all binding errors.
     * Properties that were successfully updated remain changed.
     *
     * @param pvs           a PropertyValues to set on the target object
     * @param ignoreUnknown should we ignore unknown properties (not found in the bean)
     * @throws InvalidPropertyException     if there is no such property or
     *                                      if the property isn't writable
     * @throws PropertyBatchUpdateException if one or more PropertyAccessExceptions
     *                                      occurred for specific properties during the batch update. This exception bundles
     *                                      all individual PropertyAccessExceptions. All other properties will have been
     *                                      successfully updated.
     * @see #setPropertyValues(PropertyValues, boolean, boolean)
     */
    void setPropertyValues(PropertyValues pvs, boolean ignoreUnknown)
            throws BeansException;

    /**
     * Perform a batch update with full control over behavior.
     * <p>Note that performing a batch update differs from performing a single update,
     * in that an implementation of this class will continue to update properties
     * if a <b>recoverable</b> error (such as a type mismatch, but <b>not</b> an
     * invalid field name or the like) is encountered, throwing a
     * {@link PropertyBatchUpdateException} containing all the individual errors.
     * This exception can be examined later to see all binding errors.
     * Properties that were successfully updated remain changed.
     *
     * @param pvs           a PropertyValues to set on the target object
     * @param ignoreUnknown should we ignore unknown properties (not found in the bean)
     * @param ignoreInvalid should we ignore invalid properties (found but not accessible)
     * @throws InvalidPropertyException     if there is no such property or
     *                                      if the property isn't writable
     * @throws PropertyBatchUpdateException if one or more PropertyAccessExceptions
     *                                      occurred for specific properties during the batch update. This exception bundles
     *                                      all individual PropertyAccessExceptions. All other properties will have been
     *                                      successfully updated.
     */
    void setPropertyValues(PropertyValues pvs, boolean ignoreUnknown, boolean ignoreInvalid)
            throws BeansException;

}
